Cellular phones have become very popular, not only for transmission of voice, but also for the transmission of text, data, and multimedia, converged to a form of a wireless PDA or a computer. In many parts of the world, cell phones and related technologies help people to become more mobile and resourceful. With ease of communication and speed and availability of data, all other industries, cultures, and most aspects of daily life have been influenced and drastically changed.
Despite the advantages of wireless, remote, or mobile communication and computation, one problem has not been solved yet. Because the wireless phones, pagers, radios, PDAs, gadgets, hand-held devices, appliances, or computers are in close proximity to the users' bodies, the radiated electromagnetic fields interact with nearby biological tissues. The antenna gain, radiation pattern, and input impedance are modified. In addition, the power absorption and signal blocking by human head, hand, and other parts of the body, with corresponding health concern and complications (such as brain cancer), require immediate solution and action by the hardware manufacturers, service providers, regulators, health organizations, consumer advocates, scientific communities, and government agencies around the world.
Jensen et al. studied the electromagnetic interaction of handset antennas and a human in personal communications (Proceedings of the IEEE, Vol. 83, No. 1, January 95, pages 7–17), with some suggestions for the design of the antennas. In addition, the same group and other researchers have studied the same subject extensively. For example, see the references cited in the Jensen et al.'s article (Proceedings of the IEEE, Vol. 83, No. 1, Janaury 95, pages 16–17). None of these references have a very effective solution for the radiation problem (absorption by user's body, and its health consequences, such as brain cancer).
U.S. Pat. Nos. 5,777,586, 5,666,125, and 5,507,012 (by Luxon et al.), U.S. Pat. No. 5,867,129, Khamis et al. (U.S. Pat. No. 5,930,729, for range extension accessory), and Matsumoto et al. (U.S. Pat. No. 5,949,377, for retractable, extendable, and rotatable dual antenna system, in which the second antenna is attached to the tip of the first antenna) deal with the antennas in various capacities. None of these patents have a very effective solution for the radiation problem.
Retractable antenna and rod-under-antenna have been suggested by various groups (to increase the distance between the antenna and the user), however, the antenna is still close to user's body. Thus, these are not effective solutions for the radiation problem.
Shielding devices are also used with the intention of reducing the radiation problem (such as the one offered by Marketing Future Inc.), and many patents have been issued for the design of antenna shield, such as U.S. Pat. Nos. 5,335,366, 4,471,493, 5,507,012, 5,666,125, 5,694,137, 5,564,085, 5,444,778, 5,541,609, 5,373,304, 5,336,896, 5,535,439, 5,657,386, 5,613,221, 5,726,383, 5,777,261, 5,777,586, 5,826,201, 5,940,039, 6,088,603, 6,095,820, 6,112,106, and 6,075,977. However, due to still close proximity of the antenna to the user's body, the radiation problem still exists. In addition, if the shield is misused or badly designed, in some situations (when the shield blocks the good reception for antenna), there could be an increase in bodily absorption of energy (because the cell phone increases its power output accordingly, to compensate for the bad or reduced reception). In summary, shielding is not an effective solution for the radiation problem.
Obviously, the farther away from the antenna, the less power absorption by the user's body (very roughly, goes by the ratio of square of distance values). In our current invention, we teach a new method and system to increase the distance between antenna and the user. However, let's look at the other related technologies, first.
Jabra EarBoom (by Jabra Corporation of San Diego, Calif., under U.S. Pat. No. 5,659,156, at Internet address: wwwjabra.com) offers an ear-piece (in combination with a microphone) which connects to the cell phone by a wire (connector), for hands-free mobility. This is also somewhat helpful to reduce the radiation absorbed by the user to some extent, by increasing the distance between the user and the antenna. However, to prevent the wire being entangled, they usually keep the length of the wire short. Therefore, the radiation problem still exists. In addition, having a short wire, the choices of positioning the handset is limited. If they had made the wire longer, then the wire would have been more likely to become entangled, effectively making the distance between the user and the antenna shorter again, which means more radiation absorption by the user's body. Furthermore, sometimes, when an entangled or a long wire accidentally gets yanked, the thin metal in the wire gets disconnected permanently, rendering the ear-piece useless. In short, the radiation problem is not effectively solved by this method, and this is not a convenient solution.
Other cellular headsets, such as over-the-head cellular headset (for example, Plantronics M110 and M114, sold by headsets.com), on-the-ear cellular headset, and in-the-ear cellular headset, have wire connections, and thus, have the same problems as those of Jabra EarBoom, mentioned above.
Similarly, PC headsets, such as Plantronics LS-1 Analog PC Headset, have wire connections, and thus, have the same problems as those of Jabra EarBoom, mentioned above.
Other corded headsets, such as GN Netcom Orator, Headsets.com Executive 2 Elite Over-the-Head, and Plantronics Mirage (H41), have wire connections, and thus, have the same problems as those of Jabra EarBoom, mentioned above.
Headsets.com (a headset specialist on the Internet) also sells a wireless headset called GN Netcom Bluetooth (GN 9010-BT), which lets the user roam around the office with the headset, free of any wiring or connection to the base or main part of the phone, for hands-free comfort and mobility in the office, using Bluetooth technology. The problem with this headset is that it only works with Bluetooth-enabled appliances, and within that (Bluetooth) environment (within a short range of distances). Thus, for example, the user can work in his office with other Bluetooth-enabled appliances, but the user cannot operate that in his car, in his house, or in the park, where other Bluetooth-enabled appliances are not available. In addition, the headset is intended to be used with a desktop phone. That is, according to the manufacturer's (GN Netcom) web site (gnnetcom.com), regarding the specification of GN 9010-BT complete unit, the unit consists of a headset and a base station, and the base station part of the unit is connected to a desktop phone. Thus, this is different from our current invention, which is intended for wireless or mobile environment.
Other wireless headsets (for example, by the manufacturers mentioned above, or HelloDirect.com, a division of GN Netcom), such as Plantronics CA10/CS10, Plantronics CT10, GN Netcom 2.4 GHz Ellipse, GN Netcom 9050, GN Netcom 9020-D, and GN Netcom GN 9000 Digital, are intended to work with a desktop phone, or have a hookswitch. Thus, this is different from our current invention, which is intended for wireless or mobile environment.
Some of the available commercial systems are useful for the mobile phone in the car, such as the antenna on the trunk of the car, or the systems that use the speakers of the radio, or use microphones attached to different parts of the car. One example is Tecno Vector (wireless infra-red full-duplex universal hands-free car kit), by TecnoZone Enterprises, LLC, sold through CompUSA store, or by tecnozone.com, which is designed for cell phones in cars. However, most of these systems are not practical for a user walking in the street, for example. Thus, one needs a more general or comprehensive solution, for any type of users, especially for mobile users.
Note that Logitech cordless telephone, PC, and VoIP headsets also have similar features as those of other manufacturers, described above. Thus, this is different from our current invention, which is intended for wireless or mobile environment.
Mobile computing products, such as PicoBlue Access Point for accessing the network via a Bluetooth-enabled device (offered by mobileplanet.com), have some of the same problems described above for GN Netcom Bluetooth (GN 9010-BT).
(Note that different kinds of hands-free speaker phones fall into one of the categories above. Thus, they have already been discussed in the previous paragraphs.)
Conventional (desktop) cordless phones, such as 2.4 GHz models by Panasonic, Siemens, Vtech, or Uniden (single-line or multi-line expandable), are also different from our current invention, because the base station itself is not wireless or mobile.
Conventional radios (or pagers) are also different from our current invention, because the radio is close to the user's body.